Psoriasis is a common chronic, recurrent, inflammatory disease of the skin characterized by rapid multiplication and turnover of the epithelial cells with a consequent thickening of the epidermis, as well as an accumulation of incompletely maturized cells in the stratum corneum resulting in dry scaling patches. Its etiology is unknown and presently available therapeutic agents are generally not satisfactory. The disease is estimated to affect as much as 1-2% of the population and, while not fatal, it is socially, psychologically, physically and economically crippling to its victims.